The series follows a bumbling and incompetent cyborg cop named Inspector Gadget, who is sent on cases and missions by his boss, Chief Quimby. These schemes are often caused by his arch-nemesis, the evil Dr. Claw. With the unknown help of his brainy niece, Penny and her dog, Brain, Gadget always comes on top. Usually resulting in Claw vowing revenge.
- Inspector Gadget ― Voiced by Gary Owens in the original version of the pilot and by Don Adams in the re-dubbed version of the pilot and the rest of the series.
- Dr. Claw/Brain/M.A.D. Cat- Frank Welker.
- Penny Brown ― Mona Marshall in the pilot, Cree Summer in the rest of the first season and Holly Berger in the second season.
- Chief Quimby ― Dan Hennessey in the first season and Maurice LaMarche in the second season..
- Corporal Capeman ― Townsend Coleman.